your turbo would find it hard to spool going up gears , ok for first and second but will toil to build boost 3rd upwards the dump valve essentially stops backpressure causing the turbo to STALL ! and hence taking longer to spool up which is lag as its known obviously
other than that removing it would only cause lag
without the dv you would get the same WHOOSH NOISE but it would be coming from the mouth of the turbo rather than the dv , that woosh noise without a dump valve which can be heard on fiesta rs turbos and escorts without dv's is basically the air travelling out backwards to the only point of pressure release ( the air filter track )
so basically it would be fine to remove it just as long as ur wiling to put up with the above until a better one is sourced
